Air Pollution Exposure during Pregnancy and Childhood Autistic.pdf

Environmental Health Perspectives ? volume 124 | number 1 | January 2016 133 Research | Children’s HealthA Section 508–conformant HTML version of this article is available at /10.1289/ehp.1408483. Introduction Autism spectrum disorders (ASD) are lifelong developmental disabilities characterized by social interaction impairment, commu- nication deficits, and repetitive behaviors (van Engeland and Buitelaar 2008). The prevalence of ASD has increased in the past 20 years, reaching 1 in 86 children in Europe in 2007 (Posada et al. 2007). Despite advances in genetic research, the causes of ASD remain unclear (Betancur 2011). A possible etiologic role for environmental factors has been suggested, particularly during pregnancy (Dietert et al. 2011). Two recent case–control studies in California showed that ASD in children 2–6 years of age was associated with prenatal exposure to traffic-related air pollutants (Becerra et al. 2013; Volk et al. 2011, 2013), but the results of a twin study from Sweden did not confirm that finding (Gong et al. 2014). Another case–control study among children of Nurses’ Health Study II participants reported an association between prenatal exposure to PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) (Raz et al. 2015) and other air pollutants Address correspondence to M. Guxens, Centre for Research in Environmental Epidemiology, Carrer Doctor Aiguader 88, 08003-Barcelona, Spain. Telephone: 34 932147394. E-mail: mguxens@creal.cat Supplemental Material is available online (http:// /10.1289/ehp.1408483). We thank all participants for their generous collaboration. Funding was provided as follows: ESCAPE Project— European Community’s Seventh Framework Program (FP7/2007-2011-GA#211250). CATSS, Sweden— Swedish Research Council for Health, Working Life and Welfare (FORTE), Swedish Research Council (VR) Formas, in partnership with FORTE and VINNOVA (cross-disciplinary research program concerning chil- dren’s an